The incidence of pertussis infection has been effectively controlled by use of current whole cell pertussis vaccines. However, recent advances identifying pertussis toxin (PT) as a major protective antigen against B. pertussis infection and disease affords an opportunity to produce a new pertussis vaccine with improved safety and efficacy. Another project (Z01 HD 01302) is in progress directed at characterizing the biochemical action of PT. The current project concentrates on development of methods for production of large amounts of toxin as well as methods for neutralization of toxic action and assessing the immune response to toxins thus neutralized. By this appproach it should be possible to establish a scientific basis for the development of a new pertussis vaccine. In order to obtain sufficient amounts of PT to permit studies on vaccine development, studies were initiated to establish conditions via which growth of the organism could be achieved in large scale fermentators. After extensive study, growth conditions and inoculum size have been established permitting large scale cultivation of the organisms. A suitable anti-foam was found which does not adversely effect bacterial growth or PT production, and optimal conditions for aeration during growth were established. Additional studies are in progress to determine factors which might lead to enhanced PT production. In addition, enzyme linked immunoabsorbent assays (ELISA) are under development which will permit quantitation of the immune response elicited by the various preparations of inactivated pertussis toxin. By using this approach it should be possible to establish what methods of inactivation are suitable for preparation of effective immunogens.